Yours

Yoga

Free to read here, from Project Gutenberg.

The Yoga Sutras of Patanjali: The Book of the Spiritual Man

Patañjali, also an audiobook

The Hindu-Yogi Science of Breath

William Walker Atkinson, also an audiobook

A Series of Lessons in Raja Yoga

William Walker Atkinson, also an audiobook

An Introduction to Yoga

Annie Besant, also an audiobook

Mystic Christianity; Or, The Inner Teachings of the Master

William Walker Atkinson

Yoga as philosophy and religion

Surendranath Dasgupta

The Doctrine and Practice of Yoga

A. P. Mukerji, swámi